1. Field of the Invention
The invention relates to a driving method and a liquid crystal display device to restrain flickers.
2. Description of the Related Art
A liquid crystal display device comprising thin film transistors (TFTs) is an active-matrix liquid crystal display device. Each of the TFTs serves as a switching element and is disposed in each pixel. The switching element transmits a signal voltage (e.g. image signal voltage, and comprehensive voltage) to a pixel electrode. Thus, crosstalk does not occur between pixels and the liquid crystal display device achieves high resolution and is capable of displaying different color-depths.
When the liquid crystal display device is employed in an electronic device, if the electronic device utilizes battery power, power consumption of the liquid crystal display device becomes an important factor. Meanwhile, the electronic device may be a mobile data terminal apparatus. Conventional methods (e.g. Japanese Patent Application No. 2004-536347 and 2006-523323) design pixels to have a storing function.
In a liquid crystal display device, which is a dynamic memory type, a storing unit (e.g. dynamic random access memory (DRAM)) is disposed in an output side of each TFT. Each TFT is disposed between an intersection of a source bus line and a gate bus line. The storing unit stores display data such that the stored display data can be displayed in the liquid crystal display device.
In the dynamic memory type, the storing unit is required to be periodically refreshed to maintain the stored data in the storing unit. Particularly, the storing function is embodied according to poly-si semiconductor. Current leakage is increased such that visible flicker.
Thus, to restrain flicker, the periodic refreshing period may be reduced. However, reduction in the periodic refreshing period causes that the writing actions of pixels and peripheral circuits and power consumption are increased. In other words, when power consumption is reduced, the flicker is increased. Similarly, when the flicker is reduced, power consumption is increased. Thus, a liquid crystal display device having low power consumption and is capable of restraining flicker is desired.